Abstract:

The present paper focuses on the unified modeling suite for
annular flow that the authors have been developing in the last
few years. Annular two-phase flow is one of the most important
of the gas-liquid two-phase flow regimes because of the large
range of industrial applications in which it occurs, such as
refrigeration and air conditioning systems, nuclear reactors and
chemical processing plants, and high heat flux cooling
applications. Sound design and safe operation of two-phase
flow systems require accurate modelling of annular flows, and
this motivated the development of the mechanistic modelling
suite for annular two-phase flows that is discussed here. First,
the unified suite of annular flow prediction methods is
presented, illustrating in particular the most recent updates.
Then, selected results for convective evaporation and
condensation in tubes and channels are presented and
discussed. Presently, the annular flow suite includes prediction
methods for the void fraction, the entrained liquid fraction, the
pressure gradient, and a turbulence model for momentum and
heat transport inside the annular liquid film. This turbulence
model, in particular, allows prediction of the local average
liquid film thicknesses and the local heat transfer coefficients
during convective evaporation and condensation. The benefit of
a unified modeling suite is that all the included prediction
methods are consistently formulated and are proven to work
well together, and provide a platform for continued
advancement based on the other models in the suite.

Description:

Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016.